Re-edited feature version of serial The Phantom Empire (1935). Singer Gene Autry discovers a race of advanced humans living beneath the earth.
The cunning Cardinal Richelieu must save King Louis XIII from treachery within his inner circle.
A young pacifist after refusing on principle to defend her sweetheart's honor and being banished in disgrace, joins a riverboat troupe as a singer, acquires a reputation as a crackshot after a saloon brawl in which the villain of the piece accidentally kills himself with his own gun, falls in love with his former fianceé's sister and finally bullies an apprehensive family into accepting him.
When the ancient continent of Mu sank beneath the ocean, some of its inhabitant survived in caverns beneath the sea. Cowboy singer Gene Autry stumbles upon the civilization, now buried beneath his own Radio Ranch. The Muranians have developed technology and weaponry such as television and ray guns. Their rich supply of radium draws unscrupulous speculators from the surface. The peaceful civilization of the Muranians is corrupted by the greed from above, and it becomes Autry's task to prevent all-out war, ideally without disrupting his regular radio show.
Jim Malvern is one of the richest men in the world. Unscrupulous and greedy, he uses beautiful young women as his playthings. But after meeting gorgeous actress Gloria Dawn, Malvern decides to put aside his philandering ways. With a marriage date set, the millionaire invites a flock of his famous friends -- including some of his former lovers -- to a remote island. Moments before the ceremony, Malvern is shot and killed by an unseen assailant. A grieving Gloria, realizing the murderer must be one of the guests, goes on a hunt for her fiance's killer.
Two destitute New Yorkers meet cute in Central Park and then separate and independently get tangled up with some gangsters only to be reunited again in the end.
Hanley shoots a man and then frames Bill Roberts. Being the Judge he then holds court planning to hang Bill but Bill's friends effect his escape. Andy tries to lead Hanley astray by misleading him as to Bill's location. But Bill changes plans and Hanley catches up with him and this leads to the showdown.
Canadian Mountie Mason is sent south of the border to look for a horse thief with only a watch chain for evidence. He befriends young Andy and when Calhoun hits Andy, Mason and Calhoun fight. In the scuffle Calhoun's watch with the missing chain is dislodged. Mason then sets out to bring in Calhoun and his gang.
Acting on a tip from former stage actress Fern Madden, who is now working as a movie extra, Jimmy Burke, a Hollywood reporter, publishes an article revealing an independent film producer to have mob connections. As a result of the story, Jimmy becomes city editor.
Billy, after shooting down land baron William Donovan's henchmen for killing Billy's boss, is hunted down and captured by his friend, Sheriff Pat Garrett. He escapes and is on his way to Mexico when Garrett, recapturing him, must decide whether to bring him in or to let him go.
Two pals enlist in the army during World War I. Just before they complete training camp and are to be sent overseas, they're scheduled to marry their girlfriends. However, they get in trouble and wind up in the guardhouse. Their girlfriends are determined to get married, however, and in order to accomplish this, they disguise themselves as soldiers and sneak onto the base, where they unwittingly get mixed up with enemy spies trying to gather information.
Despondent over the infidelity of his wife, William McCabe wanders on the waterfront considering suicide, but instead he saves the life of Shark Moran. Moran gives McCabe a job on his lightship, where McCabe enjoys the solitude and falls in love with Ann Reynolds, the daughter of the captain of the supply ship.
Son of Colonel Haddington, Bob leads a posse against raiders in a settlement. During his absence, one of the prize horses is stolen and his father is killed. Bob swears revenge and becomes known as Velantrie, leader of a band of semi-outlaws, and befriends a priest, Father Hillaire. At a mission, he meets Val, daughter of John Hannon, a wealthy ranch-owner.
An Englishman goes undercover posing as an Egyptian sheik in order to infiltrate a conspiracy to throw off British rule. An English woman complicates things by falling in love with the sheik, unaware of his true identity.